Crucible melting-furnace.



W. MELAS.

GRUCIBLE MELTING FURNACE.

APPLICATION FILED SEPT. s, 1911.

1,086,835. Patented Feb. 10, 1914.

7 SHEBTS-SHBET 1.

ATTORNEYS AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA c4 Patented Feb. 10, 1914.

7 MEETS-SHEET 2.

WITNESSES ATTUHNHS} COLUMBIA PLANOGRAPH :0 WASHINGTON. D. C1

Patented Feb. 10, 1914.

7 SHEETS-SHEET 3.

QQ Q W. MELAS.

1 W .r QQ M .1.

INVENTOR ATTORNEYS GRUCIBLE MELTING FURNACE.

APPLICATION FILED SEPT. 8, 1911.

x aw I, \oww 4% W W 1 a o \W u m% w w W h Q 11 3 1 W 53 Q1 w WITNESSESW. MELAS.

GRUOIBLE MELTING FURNACE. ABPLIGATION FILED SEPT. 8, 1911. 1,086,835.PatentedFeb. 10, 1914.,

7 SHEETS-SHEET 4.

WITNESSES ATTORNEYS W. MELAS.

GRUCIBLE MELTING FURNACE.

APPLICATION FILED SEPT. a, 1911.

7 SHEETS-SHEET 5.

Patented Feb. 10, 1914.

W I I HL I I I I IIIllflllflflllllllliiffillI!!!ll WITNESSES f %7%;6

INVENTOR '7 SHEETS-SHEET 6.

Patentd Feb. 10, 1914.

W. MELAS.

GRUGIBLE MELTING FURNACE. APPLIGATION FILED SEPT. a, 1911.

WITNESSES W. MELAS.

ORUOIBLE MELTING FURNACE.

APPLIGATION FILED SEPT. s

Patented Feb. 10, 1914 7 sums-sum 7.

INVENTOR I WITNESSES ATTORNEYS COLUMBIA PLANOGRAPH Gil-,WASHINQTDN, n.c.

UNITED STATES PATENT OFFICE.

WILLIAM MELAS, 0F PHILADELPHIA, IPENNSYLVANIA, ASSIGNOR 0F ONE-HALF 'I'ODAVID TOWNSEND, OF PHILADELPHIA, PENNSYLVANIA.

ORUCIIBLE MELTING-FURNACE.

Application filed September 8, 1911.

To all whom it may concern:

Be it known that I, WILLIAM MELAS, a citizen of the United States,residing in the city and county of Philadelphia, State of Pennsylvania,have invented a new and useful Crucible Melting-Furnace, of which thefollowing is a specification.

My invention relates to furnaces for melting metals, such as steel, incrucibles, and it consists of such furnace employing a gaseous or liquidfuel such as oil or other liquid hydro-carbon.

It further consists of such a furnace in which all air admitted into itscombustion chamber is under positive control and in which undue escapeof heat from such chamber is prevented or checked.

It further consists of such a furnace in which the products ofcombustion or waste gases are conveyed from the melting furnace orcrucible chamber to a preheating chamber to there preheat chargedcrucibles before they are placed in said former furnace.

It further consists of such a furnace in which air is heated from thewalls of the furnace or combustion chamber, to provide hot air for theliquid fuel burners.

It further consists of such a furnace in which combustion air is heatedin a stove by means of the products of combustion or waste gases afterthe latter have heated the crucibles in the preheating chamber andbefore they escape from the furnace through a flue.

It further consists of such furnace in which the combustion chamber forthe melting crucibles is heated by fluid fuel burners and combustion airis heated by the heat from such chamber and from the waste gases fromsaid chamber after such gases have preheated charged crucibles Itfurther consists of improved means for removing the crucibles from thecombustion chamber. I

It further consists of improved means for retaining the heat in thecombustion chamber when removing the crucibles of molten metal.

It further consists of improved means for operating the covers of thecombustion chamber.

It further consists of other novel features of construction all as willbe hereinafter fully set forth.

Specification of Letters Patent.

Patented Feb. 10, 1914. Serial No. 648,337.

For the purpose of illustrating my invention I have shown in theaccompanying drawings one form thereof which is at present preferred byme, since the same has been found in practice to give satisfactory andreliable results, although it is to be understood that the variousinstrumentalities of which my invention consists can be variouslyarranged and organized and that my invention is not limited to theprecise arrangement and organization of these instrumentalities as'herein shown and described.

Figure 1 represents a vertical section of my improved furnace on theline m-w in Figs. 2 and 3. Fig. 2 represents a top plan view of myimproved furnace. Fig. 3 represents a horizontal section of the furnaceon the line g y in F ig.- 1. Fig. 4 represents a horizontal section ofthe furnace on the line .22 in Fig. 1. Fig. 5 represents a transversesectional view of one half of the preheating section of the furnace onthe line aa in Fig. 3. Fig. 6 represents a transverse sectional view ofone half of the preheating section of the furnace on the line 6-6 inFig. 3. Fig. 7 represents av sectional view of one of the twyers intowhich a liquid fuel burner opens into the combustion chamber, and a topview of one of the burners. Fig. 8 represents a sectional view of one ofthe crucible lifts. Fig. 9 represents a sectional view of one of theadditional caps and covers for a crucible. Fig. 10 represents aside-view of as much of the main cover of the combustion chamber as isnecessary to illustrate the application of the roller bearing lever forraising and revolving said cover. Fig. 11 represents a side-view inperspective of the lever for raising the lids to remove the crucibles.

.Similar numerals of reference indicate corresponding parts in thefigures.

Referring to the drawings, the numeral 1 indicates a suitable casing ofsheet iron or steel, into which a pipe, 2, having a gate or valVeQ opensfrom a suitable source of air. under pressure. The upper end of the casing has a series of openings, 3, which communicate with a passage, 4,around the easing, and said passage communicates with a chamber, 5,formed between a sheet-metal jacket 6, and inner sheet-metal coverings6?, and linings, 6 of mineral wool, ashes or similar material, securedagainst the walls,

7, of the combustion chamber or crucible furnace 8. Said furnace has aslag-spout, 9, extending laterally from its bottom and temporarilyclosed during the operation of the furnace by a plug, 10, of fire-clay,graphite-paste or similar fireproof material. Twyers, 11, are providedthrough which the flames from suitable liquid fuel burners, 11*, may beadmitted into the furnace. The twyers have seats, 72, shaped as asegment of a sphere, into which correspondingly shaped heads, 7 3, areseated, being capable of rocking in all directions in said seats. Saidheads have guide-rods, 74, secured in them, and the burners havelongitudinally bored lateral extensions, 7'7, sliding upon saidguide-rods and secured in their adjusted positions by set screws, 78.Nuts, 79, upon the ends of the guide-rods serve as stops for the outwardmovement of the burners. The ends, 80, of the burners arespherosegmental on the same radius as that of the heads.

The sphero-segmental heads may be rotated to adjust the jets of theburners to the most advantageous direction for the operation of thefurnace. It has been found that where highest economy in fuelconsumption is desired, such an adjustment is from time to timenecessary as the furnace lining gradually burns out or slags off,whereby the original shape and size of the combustion chamber ischanged, which also necessitates slight changes in the position of thegeometrical axis of the jet or spray which enters the furnace. This mostadvantageous direction having been experimentally determined from timeto time, the heads are securely fastened in said position by the clampscrews.

Then the heads have been properly adj usted and secured by the clamps,the burners are slid inward upon the guide-rods until their ends have anairtight fit in the seats, whereupon they are secured by the set screws.When the burners are not in operation, the set screws are loosened andthe burners slid back upon the rods until stopped by the stop-nuts, whenthey may again be secured by the set-screws. By thus withdrawing theburners undue heating of the same by the heat from the furnace isavoided. ,Each twyer has a transverse guide-way in which a slide orgate, 7 6, may move to close or open the passage in the seat and throughthe twyer. The top of the furnace is open and is covered by a circularcover, 12, consisting of a metallic ring, 13, and a fireproof body, 14.Said cover has two diametrically opposite trunnions, 15, and stops, 16,are provided upon the top of the furnace, so that the cover may berotated ninety degrees in either direction to bring either of thediametrically opposite holes, 17, in the cover to register with one offour crucibles, 18, in

the furnace. Two forked lever heads, 19, have holes by means of whichthey may be fitted to rock upon the trunnions, and the two legs of eachhead have rollers, 20, which may travel upon the top of the furnace.Each head has a socket, 21, into which the end of a lever, 22, may befitted. When it is desired to rotate the cover to bring one of theopenings in register with a crucible, the levers are inserted into thesockets of the heads and rocked to bring a roller to bear against thetop of the furnace, thus raising the cover, which may thus be rotated,traveling upon the rollers. The two openings in the cover are covered bycircular lids, 23, of fire-proof material, and said lids havediametrical trunnions, 23, which may be engaged by the hooked ends of aforked lever, 24, having a fulcrum-lug, 25, which may on gage insockets, 26, in the top of the furnace. Each of the two lids may belifted and swung out of the way from the opening by this lever so as togive access to a crucible beneath it. Each crucible rests upon adownwardly flaring cap, 27, preferably formed from the bottom of aworn-out crucible, and having a filling, 28, of graphite, which fillingis formed with a diametrical groove, 29, engaged by a diametrical rib,30, upon the upper end of a head, 31, of a plunger-tube, 32. Said tubehas a tubular-jacket or covering, 33, of graphite or similar highlyrefractory material, and said covered tube slides in an opening, 34, ofsomewhat greater diameter, in the bottom of the furnace, surrounded by aboss, 35, which prevents any overflowing metal or slag from entering thebearing. A sleeve, 36, surrounds the lower end of the plungertube,adding weight to it and serving as a stop to prevent excessive upwardmovement. An upright tube, 37 is supported upon the bottom of theair-chamber and has a piston 38, upon its upper end, upon which theplunger-tube slides.

A pipe, 40, leads from a source of fluid under pressure and extendsaxially through the tube, opening through the piston, and fluid underpressure may be admitted through said pipe to raise the plunger-tube andthe crucible thereon. A nipple, 41, extends from the lower end of thesleeve and has a chamber, 42, formed within it, having a valve-seat, 43,and a channel, 44, communieating through the sleeve and plunger withinthe latter and beneath the piston. A bushing, 45, upon the inner side ofthe plunger-tube forms a substantially airtight sliding joint between itand the piston-tube 37.

A screw-valve, 46, is threaded through the outer end of the nipple,entering the chamber in the same and adapted to fit on the seat, andsaid valve has an axial bore, 47, opening through its side. Thescrew-valve may be adjusted in its relation to the seat 13:3

to allow more or less air to enter or escape from beneath the pistonduring the descent or ascent of the plunger-tube, thus regulating thespeed of the same by adjustment of the vent.

Two ducts, 48. lead from the furnace or combustion chamber to twocrucible preheating ovens, 49, the open tops of which are closed byremovable covers, 50, and said ducts convey the products of combustionand waste gases to said preheating ovens to heat charged crucibles, 51,before they are placed into the melting furnace. Beneath the cruciblepreheating ovens are pairs of chambers or stoves, 52, into which leadducts, 53, from said latter ovens. The chambers of each pair areseparated by a wall, 54, having openings, 55, near its foot, throughwhich communication is provided between each pair of chambers. Flatair-fines, 56, rectangular in cross-section are arranged in the chambersand spaced so that the products of combustion may have access to allsides of said fines, and the upper and lower ends of each set .of saidfines are connected in pairs by means of coupling-boxes, 57, so that airentering the upper end of a flue at one end of a series will beconducted down and up through a series, emerging at the lower end of thelast flue of the series and passes through a duct, 58, to the series inthe ad joining chamber, where it passes through the fines in the samemanner as in the first series, emerging at the upper end of the lastflue into a chamber, 59, whence the hot air is conveyed by a duct, 60,to ducts, 61, in the walls of the combustion chamber. Each end of eachof said ducts opens into the combustion chamber through an opening, 62,registering with a burner, so that the jet of the same is mixed with thehot air. The air for the preheating flues passes from the air-supplypipe 2, casing 1, passage st and the chamber 5 surrounding the combustion chamber, through ducts, 63 connecting with said chamber, to thefirst flue of each of the two series of air-flues. whereby theair-supply to the combustion chamber is preheated in the twoair-preheating chambers or stoves. A flue, 6 f, conveys the products ofcombustion and waste gases from the two chambers.

The crucibles are of the ordinary shape employed in furnaces of thischaracter. and are preferably made from graphite. Inasmuch, however, asa crucible packed with pieces of steel or other metal will not hold asmuch as the same size crucible will hold when the metal is melted, Iprovide a truncate conical extension, 65, also of graphite, which isfilled with metal and preheated like the crucibles, finding room in thespaces between the latter in the preheating oven. To retain the piecesof metal in the extension.

65 I provide a bottom, 66, and a top, 67, of

iron or steel, connected by wires, 68. The upper end of the extension isclosed by a domed cover, 69, which is also preferably filled with metal,and I form such cover with a hole, 70, in its top, for the insertion ofa hook for removing the cover or of a rod to test the condition of themetal in the extension. The hole is preferably closed by a shard, 71,from a broken crucible.

lVhen the charged crucible, extension and cover have been sufiicientlypreheated, they are removed from the preheating oven, put together, andplaced upon the cap of a raised plunger cylinder which is thereuponlowered into the furnace and the opening closed by its lid. hen the heatin the furnace melts the contents of the crucible, extension and cover,the metal bottom and top of the extension will also melt and allow thecon tents of the extension and cover to flow into the crucible,whereupon the cover may be removed by a hook inserted into the hole inthe same and the extension may be removed by tongs and the top of thecrucible covered by a cover, whereupon the crucible may remain in thefurnace until the metal is properly melted. hen this occurs, thecrucible is raised by the lift after the cover has been rotated to bringan opening to register with it and after the lid has been removed. Verylittle heat will escape from the furnace while the crucible is removed,as the cap nearly fills the opening. A preheated crucible may nowreplace the one removed, and the process continued indefinitely. Attimes it may happen that slag or metal overflows the crucible and flowsdown to the face of the cap where it chills and cements the crucible tothe cap. This seal may be broken by rotating the crucible by the tongs,the cap is prevented from rotating by the tongue on the head of thcplunger-cylinder engaging the groove in the filling of the cap.

By the employmentof the fluid-actuated lifts, very little heat escapesfrom the furnace when removing a crucible, as the cap or cruciblesupport nearly closes the opening in the cover. This is an item of greatimportance, as the escape of heat while removing a crucible from withinthe furnace by hand-adjusted tongs admits of a considerable escape ofheat and consequent loss'of heat in the furnace, which will require aproportionate consumption of fuel to restore. From practical tests andexperience, I have found that the act of removing a crucible by manuallyadjusted tongs and lifting the crucible by a crane or similar hoist,occupies at least one-half minute, while in my furnace the crucible maybe raised and the tongs of the traveling hoist adjusted in not more thanfive seconds. Consequently, the metal in the crucible will reach themolds at a higher temperature and in a more liquid condition. This is animportant advantage as the amount of heat units emitted from a body inunit time is in direct proportion with the difference of the fourthpowers of the temperature of the body and the surrounding medium. Theunavoidable loss of heat which is very high at high temperatures can becut down materially by shortening the total time of exposure of the hotbody as much as possible and it is the object of this invention toprovide means whereby said time of exposure of the interior of thefurnace and of the crucibles is actually and considerably diminished incomparison with the heretofore usual practice. By tests with opticalpyrometers, I have found that the reduction in temperature of a crucibleheated to 2000 centigrade (the usual temperature in my furnace) duringfive seconds exposure to the atmosphere amounts to 800 centigrade.

The openings in the furnace walls from the hot-air ducts in the same,and through which the jets of mixed oil and air are injected into thefurnace are arranged near or in the corners of the same and open so thatthe flames assume a rotary or swirling motion, thereby producing uniformheating of the entire furnace. The jet of fuel from the twyer intersectsthe current of intensely heated air in the hot-air ducts 61 and ishighly heated, vaporized and expanded, and completely mixes with theheated combustion air and this mixture is not ignited until the same haspassed through the opening in the hot-air passage.

While the furnace is here disclosed as square in plan, the furnace maybe constructed polygonal or round, when the twyers and burners willstill be arranged so as to produce tangential flame jets creating theswirling 'llame motion, as will readily be understood without additionaldescription and illustration.

As the walls of a furnace of this character quickly crack under theintense heat in the same, the air-chamber is formed by a completelyclosed casing, G-6, so that none of the comparatively cold air in saidchamber can enter the furnace and cool off the fire therein.

The plungers of the crucible lifts will be cooled in the base casing bythe cold air entering the same, and the caps or crucible supports willbe cooled by cold air ascending through the spaces between the openings3 and the plunger-s and impinging against the under sides of the flaringrims of the caps.

The air entering the casing will be heated by contact with the bottomand sides of the furnace, in turn cooling said parts, and admission orentrance of air to the furnace is solely controlled by the valve or gate2* in the air supply pipe, as no access of air from the surroundingair-chamber can be had into the furnace through the sheet-metal sides ofthe same.

As the products of combustion leave the crucible preheating chamber andenter the top of one of the chambers of a stove, then pass down andenter the second chamber of the stove through the opening at the foot ofthe partition-wall and again pass upward to discharge into the stack, itis obvious that the greater part of the heat of such products will be.given off to the airfiues in the preheating-stoves.

The air-flues in each of the preheatingstoves form a continuous tortuouspassage, the receiving portion of which is in that portion of the stovewhere the products of combustion are discharging and are, consequently,least hot, while the discharging portion of the passage is in thatportion of the stove where the products of combustion enter and are,consequently, the hottest. By this construction the intensely hotcombustion air which produces the high-temperature combustion in thecrucible furnace is attained and the process of melting highlyrefractory metals greatly accelerated. The air-fines, being flat incross-section and extending vertically up and down in the stoves withspaces between them, will offer large heating surfaces to the productsof combustion passing through the stoves.

The sphero-segmental shape of the heads of the burners and their seatsin the twyers will form perfectly fitting closure at each twyer, so thatno leakage of cold air will take place at the seats.

When the operation of the furnace is stopped, the gates are moved toclose the twyer openings and the burners are withdrawn. ll hen the gatein the cold-air supply pipe is closed, the furnace is completely shutoff from inlet of cold air and will retain its heat, so that, if againstarted within reasonable time, it will not require as much reheating asif air had been freely admitted and it was necessary to heat the coldfurnace.

The operation of this furnace is continuous when once started, and wastegases from the combustion chamber preheat the cruci bles and the blastair, so that the best possible use is made of the heat generated in thecombustion chamber.

lVhile the furnace is illustrated and described employing liquid fuel orgaseous fuel, it evident that other forms of fuel may be employed. Also,while the furnace is disclosed as square or rectangular with squarecorners, it is evident that change may be made in the plan or shape ofthe furnace without change in its operation or advantages.

Other modes of applying the principle of my invention may be employedfor the mode herein explained. Change may therefore be made as regardsthe mechanisms thus disclosed, provided the principles of constructionset forth, respectively, in the following claims are employed.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent, is

1. An apparatus of the character stated, comprising a singlecombustion-chamber and crucible melting furnace having a solid bottom,burners for gaseous fuel above said bottom, a crucible preheating oven,a flue directly connecting said furnace and oven to carry the productsof combustion from the former to the latter, an air-preheating stove, aduct from the crucible-preheating oven to said stove, and an air-ductfrom said stoveto the burners of the furnace.

2. An apparatus of the character stated, comprising a crucible furnaceprovided with burners, an air-chamber surrounding said furnace, meansfor supplying air under pressure to said chamber, a crucible preheatingoven connected to said furnace to receive the products of combustionfrom the same, an air preheating stove connected to receive the productsof combustion from said oven and having an air-flue, a passage from theair-chamber around the furnace to said airflue, and a passage from saidflue to the fur nace,

3. In apparatus of the character stated, a crucible furnace having meansfor heating it, a plurality of individual fluid-pressure actuated liftsin the bottom of said furnace and upon each of which a crucible may restand by which they may be raised and a plurality of removable lids in thetop of said furnace and registering with said lifts.

at. In apparatus of the character stated, a crucible furnace havingmeans for heating it, a plurality of fluid-pressure actuated liftsvertically movable in the bottom of the furnace and upon which thecrucibles rest, a rotatable cover for the top of the furnace and havingopenings adapted to be brought to register with the crucibles and lifts,and removable lids for said openings.

5. In apparatus of the character stated, acrucible furnace having meansfor heating it, a vertical pist0ntube beneath the bottom of the furnaceand having a duct for the pressure fluid through it and a piston uponits upper end, a plunger-tube sliding upon said piston and having abushing in its lower end sliding substantially airtight upon thepiston-tube and a support for a. crucible on its upper end, and anadjustable vent at the lower portion of said plunger tube.

6. In apparatus of the character stated, a crucible furnace having meansfor heating it and formed with an opening in its bottom surrounded by aboss, a piston rigidly supported beneath said opening, a plunger-tubesliding upon said piston and through said openingand having the. portionsliding within the furnace covered by a jacket of refractory material, ahead secured upon the upper end of said tube and formed with adiametrical rib on its upper face, a downwardly flaring cruciblesupporting cap having a filling formed with a diametrical groove fittingsaid rib, and means for admitting and exhausting pressure fluid betweenthe piston and the head.

7. In apparatus of the character stated, a crucible furnace having meansfor heating it and formed with a slag-spout near its bottom and with anopening in its bottom surrounded by a boss, a plunger sliding in suchopening and covered with a jacket of refractory material, means forraising and lowering said plunger, and a downwardly flaringcrucible-supporting cap upon the upper end of the plunger.

8. Apparatus of the character stated, comprising a casing having meansfor admitting air under pressure into it, a crucible furnace above saidcasing and having means for heating it, an air-chamber surrounding saidfurnace and communicating with the interior of said casing, a preheatingstove, a passage from the furnace to said stove, an air-heating flue insaid preheating stove, and a passage from the air-chamber around thefurnace to said flue.

9. In apparatus of the character stated, a crucible furnace having anopening in its top, a circular cover for said opening and formed withdiametrically opposite trunnions and with diametrically oppositeopenings to register with the crucibles, stops upon the top of thefurnace to engage the trunnions, and forked levers pivoted upon thetrunnions and having rollers journaled in the ends of their limbs.

10. In apparatus of the character stated, a crucible furnace having anopening in its top and formed with sockets adjacent said opening, acircular cover for said opening and formed with diametrically oppositeopenings to register with the crucibles and provided with means forrotating it, lids for said openings and provided with trunnions, and aforked lever having hooks at the ends of its limbs to engage suchtrunnions and a fulcrum-lug adapted to engage the sockets in the top ofthe furnace.

11. Apparatus of the character stated, comprising a crucible furnaceformed substantially square, and burners in the corners of said furnaceand arranged to each direct its flame along the adjacent wall, whereby acircular or swirling motion of the flames and products of combustion isattained.

12. Apparatus of the character stated, comprising a crucible furnacehaving a substantially square plan, hot-air ducts having openings at thecorners of said furnace to direct the blast from each opening along theadjacent wall of the furnace, means for supplying hot-air under pressureto said ducts, and burners discharging through the walls of the furnaceand into said openings, whereby a rotary swirling motion is imparted tothe flames within the furnace.

13. Apparatus of the character stated, comprising a crucible furnaceprovided with burners, an air-chamber surrounding the walls of saidfurnace, means for supplying air under pressure to said chamber, acrucible preheating chamber, a duct extending from the furnace to saidchamber, an air preheating stove beneath said latter chamber, ductsextending from said former chamber to said stove, flat verticalair-flues arranged in series in said stove and having their lower andupper ends alternately connected, a duct extending from the chamberaround the furnace to the receiving air-flue of the series, and ahot-air duct extending from the discharging air-flue of the series tothe burner openings and twyers in the furnace.

14. An apparatus of the character stated, comprising a casing havingmeans for admission of cold air, a furnace supported upon said casingand having its solid bot tom forming the top of the same, and anair-chamber surrounding and airtightly inclosing the sides of saidfurnace and communicating with the interior of said casing, whereby thesides and bottom of the'furnaces are cooled.

15. In apparatus of the character stated, a casing having means foradmission of cold air, a furnace supported upon the top of said casingand formed with a guide-opening in its bottom, a lift-plunger movable inthe casing and through said opening and forming an air-space between itand the openmg, and a downwardly flaring cruciblesupporting cap upon theupper end of such plunger, said cap being cooled by air from the casingpassing through the air-space surrounding the plunger.

WILLIAM MELAS. Witnesses:

WM. TEOHER, C. D. MCVAY.

copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. O.

